Select the paper tray setting for which you want to change the paper size on the [Tray Paper Settings] screen.
For details about how to access the [Tray Paper Settings] screen, see Displaying the Printer Configuration Screens Using the Control Panel.
Press [] to switch the screen.
Press [Custom Size].
If a custom size is already specified, press [Change].
Press [Vertical].
Enter the size of the paper using the number keys, and then press the [OK].
Press [Horizontal].
Enter the size of the paper using the number keys, and then press the [OK].
Press [OK] twice.
Press the [User Tools] key.
When loading thick paper, thin paper, or OHP transparencies, specify the paper size and the paper type.